The invention relates to a compactor machine and in particular to one of the kind operated by a pedestrian for fairly light compacting of the ground.
Compactor machines of this kind are generally known as forward vibrating plate compactors, and many slightly different forms are known. In general they comprise an engine which transmits power via a pulley belt to an eccentric mass unit attached to a base plate. The mass is rotated generating a centrifugal force, and simultaneously applying a downward force with motion in a forward direction. The machine is guided by a pedestrian operator via a steering handle.
A major problem with many of the prior ale compactors of this type is the level of vibration transmitted to the hands of the operator, and generally known as Hand-Arm Vibration (H.A.V.). Various approaches to the problem have been tried without much success, as significant vibration is still transmitted. This can lead to a medical condition, commonly known as Vibration White Finger, in operators who use these machines for extended periods of time, and which is clearly undesirable. The European Union has issued guidelines for safe levels of H.A.V., which can be experienced over an eight hour duration, of 2.5 msxe2x88x922. If manufacturers produce machines with levels of H.A.V. higher than this level they are required to state this in their product literature.
Clearly, if the level of H.A.V. can be reduced the operators"" health and comfort are considerably enhanced and longer working periods can also be contemplated.
It is an object of tie present invention to mitigate the above described problem.
According to the present invention there is provided a compactor machine of the kind controlled by a pedestrian operator and including a base plate, and mounted on the base plate an operative unit including means to cause the base plate to vibrate when in use, and a handle wherein the handle is mounted on the operative unit by means of a plurality of first damping mounts distant from the base plate, and the handle is pivotable relative to the operative unit.
The operative unit may comprise a support plate and a main frame, and wherein the handle is pivotally mounted on the main frame.
The mainframe may substantially define the outer dimensions of the operative unit.
The plurality of first damping mounts conveniently comprises four arranged substantially in a rectangle in a horizontal plane.
Preferably the handle is pivotally mounted on the main frame via an secondary frame which is mounted on the main frame by means of the plurality of first damping mounts.
The plurality of first damping mounts may have a stiffness in the range 10 to 20 Nmmxe2x88x921, or it may be in the range 12.5 to 17.5 Nmmxe2x88x921.
Preferably the operative unit is mounted on the base plate by means of a plurality of second damping mounts.
The plurality of second damping mounts generally comprises four arranged substantially in a rectangle.
Conveniently the plurality of second damping mounts have a stiffness in the range 30 to 70 Nmmxe2x88x921, or it may be in the range 40 to 60 Nmmxe2x88x921.